I am reconfiguring my circa 1900 bathroom, fixtures are from 1958 included a built in tub, cast iron sink and toilet.

I replaced the tub with a claw foot and relocated the door to where the old tub was, so with the changes to fit everything I had to move the sink and last but not least the time comes to move the toilet :(

I have a 4" cast iron soil stack from the basement and the toilet is directly over it on a lead section that fits into the top section of cast-iron (a Tee which goes to the roof vent) below the tee is a section with a WYE which has a 2" hub for the sink, joints have lead poured in.

which ever fool put the vent stack in, ran a 4' long horizontal below the joists and diagonally across them right where you have to walk. I'd like to take out the iron elbow and that 4' horizontal and run PVC up and between the joists out of the way, over and into the stack by the wall.

To do that and relocate the toilet, it has to come apart, any good way to get them apart besides cracking one of the pieces out with a sledge? I doubt a blow torch will melt the lead in the joints due to the heat sink mass.

I need to move the toilet over about 2 or 2-1/2 feet, can I run the 4" pvc horizontal or do I need to put in a WYE a section lower and 45 degree angle a pipe over to the toilet? Thanks for any comments.